freeze dried bloodworms, pellets
2 pellets in the morning, 2 at night, every other day replace a pellet with a bloodworm. skip feeding on mondays

water change 25% every week. will increase to every three days while attempting to treat with Pimafix and Aquarium Salt.

bought a betta from petco...got a Plakat because noone ever buys them and I like them...owned for 3 days now. first two days he ate his food voraciously and now he turns his nose at it. acts lethargic and floats about or sits on his little white rock, only speeding up to the top for air. i dont know if it is just me or not but his lips appear a little swollen and slightly discolored(light pale brown). im rather attached to him and dont want him to suffer... help? thank you for your time

hmmm.... what are you using for water conditioner? I do agree with chocolate though, it could be bad water quality from where you got him and he was already ill. I think the best thing you can do for him is frequent water changes and keeping an eye on him. Maybe if you can find some use IAL (Indian Almond Leave) as a tannin to help him get better - I know that the bettasafe conditioner has it in there as an extract, but if you can find almond leaves around you, that would be better. I understand that maple leaves work as well.

I like Nutrafin Betta Plus conditioner because it has almond leaf extract in it, but a lot of people here use Prime. There are lots of water conditioners on the market specifically for Bettas. But you need to remember to use it every time to remove the chlorine from the water.
Also, here's a helpful link from this forum on water changes based on the size of your tank and whether you have filteration or not: http://www.bettafish.com/showthread.php?t=115758

It also occurred to me that maybe he ran into something and injured his lip.

that might be a good idea. I'm not familiar with that kind of filter, but sometimes you can just remove the filter cartridge and not need to put anything in there (that's how my whisper filter works). Some people say that the medications that end with -fix are actually bad for bettas because some of their ingredients can coat their labyrinth lung and cause difficulty breathing. You can private message oldfishlady or sakura8 and they can help you with treatments, etc. oldfishlady tends to like to treat naturally without medications and sakura8 uses medications and knows a lot about the different kinds.
Good Luck

Ah! Found the thread. Okay. First, Choc does have a point. Unfortunately, poor Petco fish usually suffer from horrible water quality so they are often sick when we buy them. If plakats aren't purchased often, that means they sit on those shelves in those tiny cups for weeks at a time in water that can reach over 8.0 ppm of ammonia. (ammonia becomes toxic at .25ppm)

Most likely your guy has a mild bacterial infection or ammonia burns. 1 tsp of aquarium salt per gallon for 14 days can help with that. Be sure to keep track of how much water you remove during water changes, though, so you know how much salt to add back in. So if you remove 50% of the water, add back in 1.5tsps of salt. Never add back in the full amount of salt unless you've removed the full amount.

Adding API Stress Coat or Kordon Fish Protector can also help soothe ammonia burns and help protect them from further infection. You can add these products in addition to your regular water conditioner.

You can try frozen foods like frozen bloodworms to see if that stimulates his appetite.